Hi Guys,
I have a 1994 GMC suburban that I am trying to figure out why the temp gauge always reads low, I have tried to diagnose it before with no luck and when looking into it a second time I found something interesting and wanted to run it past you guys.
But first a little history :
A couple years back I got a new to me '94 suburban and when trying to diagnose a low reading temp gauge I replaced the sending unit by the spark plugs and thermostat ( 190 deg ) It did not cure my problem and I just lived with it. But now after flushing and replacing my coolant it seems to read even lower than it did before ( currently 140 max) so I decided to look into it again.
Here is what I got :
1) The suburban does get warm and throws good heat ( 120 - 140 deg. air out of the center vent according to an IR gun )
2) The IR gun shows 160-180 ish at the thermostat housing .
3) The gauge does not show movement when the thermostat opens up, but I can see it on the IR gun at the Thermostat housing ( about a 20 deg swing )
4) The hoses do get hot as you would expect .
5) No signs of overheating , but it does seem like a pig that cant get out of it way at times.
What I found is that the sending unit that I replaced a couple of years ago has 2 prongs in it , but the wiring harnes only has one wire. Not sure if this is the problem because it has always read low on the temp gauge . ( I probably just took the old unit to the part store so they could match up what was in there )
Is this the wrong sending unit for my application, or does this sending unit fit more than one application and is not the problem ?
Here are some pictures :
I have a 1994 GMC suburban that I am trying to figure out why the temp gauge always reads low, I have tried to diagnose it before with no luck and when looking into it a second time I found something interesting and wanted to run it past you guys.
But first a little history :
A couple years back I got a new to me '94 suburban and when trying to diagnose a low reading temp gauge I replaced the sending unit by the spark plugs and thermostat ( 190 deg ) It did not cure my problem and I just lived with it. But now after flushing and replacing my coolant it seems to read even lower than it did before ( currently 140 max) so I decided to look into it again.
Here is what I got :
1) The suburban does get warm and throws good heat ( 120 - 140 deg. air out of the center vent according to an IR gun )
2) The IR gun shows 160-180 ish at the thermostat housing .
3) The gauge does not show movement when the thermostat opens up, but I can see it on the IR gun at the Thermostat housing ( about a 20 deg swing )
4) The hoses do get hot as you would expect .
5) No signs of overheating , but it does seem like a pig that cant get out of it way at times.
What I found is that the sending unit that I replaced a couple of years ago has 2 prongs in it , but the wiring harnes only has one wire. Not sure if this is the problem because it has always read low on the temp gauge . ( I probably just took the old unit to the part store so they could match up what was in there )
Is this the wrong sending unit for my application, or does this sending unit fit more than one application and is not the problem ?
Here are some pictures :